\begin{thebibliography}{1}

\bibitem{oasis}
{OASIS eXtensible Access Control Markup Language (XACML)}.
\newblock \url{http://www.oasis-open.org/committees/xacml/}, 2005.

\bibitem{sunxacml}
{Sun's XACML implementation}.
\newblock \url{http://sunxacml.sourceforge.net/}, 2005.

\bibitem{policymanagement}
J.~Chaudhry, T.~Palpanas, P.~Andritsos, and A.~Mana.
\newblock Entity lifecycle management for okkam.
\newblock In {\em Proc. 1st IRSW2008 International Workshop on Tenerife}, 2008.

\bibitem{scalabilityaccesscontrol}
A.~D. Keromytis and J.~M. Smith.
\newblock Requirements for scalable access control and security management
  architectures.
\newblock {\em ACM Trans. Internet Technol.}, 7, May 2007.

\bibitem{Xengine}
A.~X. Liu, F.~Chen, J.~Hwang, and T.~Xie.
\newblock Xengine: A fast and scalable {XACML} policy evaluation engine.
\newblock In {\em Proc. International Conference on Measurement and Modeling of
  Computer Systems}, pages 265--276, 2008.

\bibitem{acp}
P.~Samarati and S.~D. C.~d. Vimercati.
\newblock Access control: Policies, models, and mechanisms.
\newblock In {\em Revised versions of lectures given during the IFIP WG 1.7
  International School on Foundations of Security Analysis and Design on
  Foundations of Security Analysis and Design: Tutorial Lectures}, pages
  137--196, 2001.

\bibitem{separation}
R.~Yavatkar, D.~Pendarakis, and R.~Guerin.
\newblock A framework for policy-based admission control.
\newblock RFC Editor, 2000.

\end{thebibliography}
